JPS6189314A - Nozzle plate for hollow fiber with modified cross section - Google Patents

Abstract

PURPOSE:A plurality of slits are arranged to form a closing loop so that interrupted parts are formed between adjacent slit ends, and a plurality of other slits are arranged so that they extend radially on the interruption parts to form the titled spinneret which gives no broken hollow fiber with high resistance to damaging. CONSTITUTION:A plurality of slits 1, 1', 1''... are arranged so that interrupting parts 2, 2', 2''... are formed between adjacent slit ends and these slits form a closing loop. A plurality of straight slits 4, 4', 4''... are arranged radially on the interruption parts 2, 2', 2''... from the inner side toward the outer side of the slits. The interruption parts prevent the spinneret from being deformed by pressure of the melted polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a spinneret used in producing bulky deformed hollow fibers by melt spinning a thermoplastic polymer compound.

(Prior Art) Conventionally, as a spinneret for melt spinning irregularly shaped hollow fibers, as shown in FIGS. 4(a) to (c) and FIG. 5,
A plurality of slits 1.1', 1'', 1''' are arranged to form gaps 2.2', 2'', 2''' between their adjacent ends and to form a closed loop. However, it is known that each slit 1.1', 1", 1"' is connected with a linear slit 3.3', 3", 3"' extending radially outward.

In this spinneret, each slit is 1.1', 1'',
The molten polymer discharged from 1" expands due to the ballast effect, and while sucking air in the gaps 2.2', 2'', and 2"', adjacent ends are fused together to form a hollow fiber. It is something to do.

However, in such a conventional spinneret, each slit 1.1', 1", 1"' is connected with a linear slit 3.3', 3", 3"' extending radially outward. Therefore, due to the action of the polymer discharged from the linear slits 3.3', 3", 3"', the slits 1.1', 1", 1.
An outward expanding force acts on the molten polymer discharged from ``'', and adjacent ends of the discharged polymer cannot be fused together in the gap, resulting in a part of the hollow part as shown in Figure 6. It is easy to produce defective fibers called broken hollow fibers.

In order to prevent the occurrence of such broken hollow fibers, the gaps between the slits 1.1', 1", 1" and 2.2', 2" must be
, 2''' should be made as narrow as possible, but this gap 2.
If 2', 2'', and 2''' are made too narrow, there will be a problem that the spinneret will be damaged by the pressure of the molten polymer applied to the spinneret during melt spinning, so there is a limit naturally.

(Object of the Invention) The object of the present invention is to solve the problems of the conventional spinneret for irregularly shaped hollow fibers, and to create a spinneret for irregularly shaped hollow fibers that does not cause broken hollow fibers and is not damaged by the pressure of molten polymer during spinning. Our goal is to provide spinnerets.

(Embedding of the Invention) The present invention provides a plurality of slits that are arranged such that a gap is formed between adjacent ends of each slit, and a closed loop is formed by the plurality of slits. , a spinneret for irregularly shaped hollow fibers, characterized in that linear slits extending radially from the inside to the outside of the closed loop are provided.

Hereinafter, the spinneret of the present invention will be explained in detail with reference to the drawings. 1(a)-(c) and FIG. 2 are enlarged plan views showing some examples of the spinneret of the present invention, in which a plurality of slits 1.1', 1'', 1''' are shown. Oh, wow, eee, □1
o, 2.2.
．． 2 radially extending from the inside of the closed loop to the outside through linear slits 4.4. 4. 4 are installed.

The slits 1.1.1.1 must be arranged so that a plurality of them are combined to form a closed loop, and when a closed loop is formed with one slit, there is a gap inside the closed loop that holds the cap member. becomes only one,
It cannot withstand the discharge pressure of the molten polymer, and the spinneret breaks during spinning. Slit 1.1.1.1
Usually, 2 to 6 are used, and 2 to 4 is particularly preferable. Slit 1.1. 1.1 has a circular arc shape as shown in Fig. 1(a) and Fig. 2, Fig. 1(b)
), a key-like shape as shown in (C), or a linear shape, or any other shape can be used.

Furthermore, linear slits 4. extend radially from the inside of the closed loop to the outside through the gaps 2, 2', 2", 2"' between adjacent ends of the slits 1, 1', 1'', 1''. 4', 4
'', 4'' are arranged, but this gap 2.2', 2'', 2''
″′ is 0, 2~0, 4 rrn, linear slit 4
．． It is desirable to select the widths of 4', 4'', and 4'' within the range of 0.05 to 0.3 nwn.
', 1'', 1 /// end and gap 2.2', 2'', 2
Straight slit 4.4', 4', 4 through ``''
It is preferable that the gap d with the side part of ``'' is 0°2 to 0.4nn.
It is desirable that the protrusion length Q from the slits 1.1', 1', 1''' to the inside of the closed loop is approximately 0.5 to 1°5IlIT1, and the ends of each slit in the closed loop do not touch each other. Do it like this.

The spinneret of the present invention can be applied to melt spinning thermoplastic polymers, and is particularly effective when used for melt spinning polyesters and polyamides.

(Function and Effects of the Invention) Generally, molten polymer discharged from a slit expands in the width direction and length direction of the slit due to the ballast effect. Next, this bulge increases in the slit width direction and decreases in the slit length direction due to surface tension. 'In a conventional spinneret as shown in FIGS. 4 and 5, the slits 1.1', 1'', 1'''
After the molten polymer discharged from the end expands,
The swelling decreases due to surface tension, and furthermore, due to the action of the polymer discharged from the linear slits 3, 3', 3'', 3''', the discharge from the slits 1.1', 1'', 1''' Coupled with the force acting on the polymer to expand outward, the adjacent ends of the discharged polymer do not fuse together at the 2.2", 2", and 2" gaps, resulting in breakage as shown in Figure 6. Hollow fibers often occur.

In contrast, in the spinneret of the present invention, the linear slits 4.4', 4", 4"' are the slits 1.1'.

1'', 1''' and through the gaps 2.2', 2.2. Therefore, the slits 1.1', 1
No outward expanding force acts on the polymer discharged from ``, 1''''. Furthermore, after the molten polymer discharged from the ends of the slits 1.1', 1'', and 1'' once expands,
Even if the swelling decreases due to surface tension, the swelling of the molten polymer discharged from the linear slits 4.4', 4', 4'' increases in the width direction, so that the gap 2.2'
, 2", 2"' parts, slits 1.1', 1", 1"'
The polymer discharged from the mutually adjacent ends of the slits 4.4', 4", 4" arranged therebetween is very easily fused. As a result, completely irregularly shaped hollow fibers as shown in Figure 3 can be stably obtained, and spinning conditions such as polymer temperature, spinning speed, polymer discharge amount, and spun yarn cooling conditions can be varied during spinning. Even if this occurs, broken hollow fibers as shown in FIG. 6 do not occur.

In addition, in the spinneret of the present invention, gaps 2.2', 2.
″, 2″′, so naturally the gap 2.2
The number of ', 2'', and 2''' is also plural, and sufficient strength of the spindle can be ensured, and the spindle will not be deformed by the pressure of the discharged polymer during spinning.

(Example) Hereinafter, the spinneret of the present invention will be further described with reference to Examples.

Example Using a spinneret having 68 spinneret holes of the shape shown in Fig. 2, nylon 6 having an intrinsic viscosity (measured in m-cresol at 25°C) of 1.30 was spun at a spinning temperature of 260°C and a discharge rate. 4
The fibers were spun at a spinning speed of 900 m/min while cooling with cooling air at a flow rate of 5 rn'/min. The slits 1.1' and 1'' of the cap hole are bored on concentric circles with a diameter of 1.5 mwn, the slit width is 0.2 mm, the length of the linear slits 4.4' and 4'' is 2 m, and the slit width is 0.
2mwn, slit 1.1', 1r/end and gap 2.
2', 2'', a straight slit 4, 1'.

The distance d from the side of 4'' was 0.3 mwn, the linear slit 4.4', the length Q of inward protrusion from 4'' slit 1.1' and 1' was llTlTl.

The spun yarn was drawn 3.3 times by a conventional method to obtain a drawn yarn of 1200 denier/68 filaments. There was almost no occurrence of fluff or lapping during drawing, and the strength during drawing was 3.2 g/de, the elongation was 38%, and no breakage in the hollow part was observed in any of the single yarns, as shown in Figure 3. It was a good hollow fiber as shown.

Comparative Example Using a spinneret having 68 spinneret holes as shown in FIG. 5, spinning and drawing were carried out under the same conditions as in the example.

The slits 1.1' and 1'' of the cap hole are drilled on concentric circles with a diameter of 1.5 mm, the slit width is 0.2 mm, the length of the linear slits 3.3' and 3'' is 11 m, and the slit width is 0
．． 2IrfrI, gap 2.2', 2'' spacing is 0.3m
Met.

Of the 68 filaments obtained, 10 filaments were found to have broken hollow portions as shown in FIG. 6, and fluff and lapping occurred frequently during drawing.

[Brief explanation of the drawing]

1 and 2 are enlarged plan views showing an example of the spinneret of the present invention, FIG. 3 is an enlarged cross-sectional view of a yarn obtained by spinning with the spinneret of FIG. 2, and FIG. FIG. 5 is an enlarged plan view showing an example of a conventional spinneret, and FIG. 6 is an enlarged cross-sectional view of a yarn obtained by spinning with the spinneret shown in FIG. 1.1', 1'', 1'''...Slit, 2.2
', 2'', 2'''...Gap, 4.4', 4'',
4'''...Linear slit, \,,:') Flea No. 2 Figure 3 Figure 4 (b) (C) Figure 5 Figure 6 Procedural Amendment Book 1975//Month -day

Claims (1)

[Scope of Claims] 1. A plurality of slits are arranged to form a gap between their adjacent ends, and the plurality of slits form a closed loop, and through the gap, A spinneret for irregularly shaped hollow fibers, characterized in that linear slits are provided that extend radially from the inside to the outside of the closed loop. 2. The number of slits forming a closed loop is 2 to 6.
The spinneret for irregularly shaped hollow fibers according to claim 1, which is